In the era marking what some might regard as a ‘rebirth’ in studying the history of the family – inaugurated formally in 1972 by the publication of the essays in Household and Family in Past Time and extended both methodologically and geographically in Family Forms in Historic Europe – a preeminent place was reserved for the measurement of the household or the co-resident domestic group. Indeed, in the context of an emerging and increasingly ‘positivistic’ approach to social history, it was almost inevitable that the household with its tangible qualities should become the focus of attention of family historians with a commitment to the quantitative analysis of historical social structures. Yet a doubt has been frequently raised as to the status of ‘residence’ as a criterion for the analysis of the family, whether comparisons are being made over space or through time. There are nonetheless perfectly sound reasons for considering that the knot of persons who sleep and frequently, if not invariably, take meals together under the same roof constitutes a unit for social analysis, and can form a basis for revealing inter-society comparisons, particularly if due attention is given to the means by which that unit has been brought together (e.g. whether initiated by marriage or through the fission of a pre-existing group). But this mode of analysis, Michael Anderson might say, is still reminiscent of studying the ‘family in a thermos flask’, and is certainly inadequate in its interpretation of households or kin groups in the matter of the economic behaviour of their members.